1. Field of the Invention
The present invention relates to an image forming apparatus. More particularly, the present invention relates to a thermal image forming apparatus adapted to form an image on both sides of a recording medium.
2. Description of the Related Art
To print an image on both sides of a recording medium, two recording heads may be provided at positions facing both sides of the recording medium. In this case, however, such an image forming apparatus is expensive.
In an alternative method, one recording head is provided and the recording head is designed to face the first and second sides of the recording medium in turn. In this case, two approaches may be considered. A first approach is to fix the recording head and invert the recording medium. A second approach is to move the recording head to positions facing the first and second sides of the recording medium.
U.S. Pat. No. 6,296,405 discloses an image forming apparatus configured based on the first and second approaches. In this patent, a recording head is installed in a rotational bracket and the rotational bracket is reciprocated between first and second positions around a pivot shaft. The first side is printed while the recording medium passes through the first position, and the second side is printed while the recording medium moves from the first position to the second position.
U.S. Pat. No. 6,601,952 discloses an image forming apparatus employing the second approach. In this patent, a support member for pressing a recording medium toward a recording head and a holding means for holding the recording medium are constructed as one rotation unit. The rotation unit is rotated to allow the recording head to face first and second sides of the recording medium.